Jean v



UNITED Sra'rns JEAN V. SKOGLUND, OF BROOKLYN, ASSIGNOR TO MARTIN KALBFLEISCHS SONS COMPANY, OF NEW YORK, N. Y.

ALUMlNOUS CAKE AND PROCESS OF MAKlNG SAME.

SPECIFICATION forming part of Letters Patent No; 526,205, dated September 18, 1894, Application filed November 28,1893. Serialllo. $532,275. (N specimens.)

To all whom t y 0076067111! entirely reduce the remaining portion of the Be it known that I, JEAN V. SKOGLUND, a ferric iron.

subject of the King of Sweden and Norway, The method of making the sizing agent is residing at Brooklyn, in the county of Kings as follows: The bauxite or similar material 5 and State of New York, have invented a new containing more or less iron is treated with and useful Improvement in Sizing Agents, to sulfuric acid to dissolve the oxid of aluminum.

be Used for Sizing Paper-Pulp, of which the The iron also enters the solution. To this following is a specification. Solution I add the weaker reducing agent,

To produce a paper pulp that will not dispreferablyasulfite or sulfurous acid, and heat 10 color, it is necessary to employ for the sizing it until the reducing action is nearly comof the pulp a compound of oxid of aluminum. pleted. I then add an estimated quantity of free from iron, or'if iron is containedit must a stannous compound, preferably stannous be in a ferrous state. The reason for this is chlorid or sulfate, and continue the boiling that ferric compounds impart to the pulp a or. heating until all of the ferric iron is re- 1 darkened or reddish'color. duced. The reducing action is facilitated by The object of my invention is to convert all the boiling or heating. If the .tin solution the iron existing in the sulfate of aluminum has been addedin excess, it may be precipiinto ferrt-us iron without the'introduction of tated with hydrogen sulfid or any other suitheavymetals or impurities in objectionable able agent.

2o quantities. To accomplish this,l use a stan- Having thus described iny invention, 1

nous compound by which I reduce all ferric claim as new, and desire to secure by Letters iron into ferrous iron, hereby removing every Patenttrace of ferric iron. The following formula 1. Analuminous cake, consisting of sulfate shows the chemical reaction: of alumina, ferrous iron, an excess of a stan- The stannic oxid does not dissolve in the 2. The method of reducing ferric iron in excess of fgee acid when sulfates or free sulsolution'with aluminum sulfate, which confnric acids are present, especially when the sists in first reducing the greater portion of 0 solution is hot. In this manner all the tin is the ferric iron by means of a weaker reducprecipitated, yielding a pure product. In ing agent, such as a sulfite or sulfurous acid,

stead of using stannous chlorid I may use and finishing the reduction with any stanstannous sulfate or other stannous comnous compound, substantially as specified pounds, such as stannous oxid or hydrate. herein. v

3 5 The price of tin being high, renders the pro- 3. The process for reducing aluminum sulcess expensive unless the precipitated tin is fate free from ferric iron, which consists in 55 regained and used over again. For this reatreating the crude material, such as bauxite, son I first reduce most of the iron with anwith sulfuric acid to dissolve the aluminum other and cheaper agent, such as sulfurous oxid and the iron oxid, adding a weaker re- 4o acid or its salts, or a hypo-sulfite or any other ducing agent such as sulfurous acid or a sulknown reducing agent. None'of these refite, then heating the solution, and finally 9o dncing agents are so active as the stannous adding any stannous compound, and continucompounds. Consequently it is difficult in ing the heating until all of the ferric iron is using themto reduce 1 ll the iron, especially reduced, substantially as specified herein.

when the liquid containing the iron is concentrated. \Vhen so much of the ferric iron JEAN V. SKOGLUND. is reduced as to leave only a trace of unre- Witnesses: duced ferric iron, I add the stannous com- E. M. CLARK,

. pound in an estimated quantity in order to O. SEDGWICK. 

